61results about How to "Reduce phase noise" patented technology

The invention provides a method for reducing light source phase noise in a double-field quantum key distribution system, which combines an optical phase-locked loop (OPLL) and a proportional integral (PI) control technology, and comprises the following steps of: firstly, performing beat frequency on laser signals of light source ends Alice and Bob, and realizing frequency locking and phase synchronization of a laser through the OPLL; on the basis, the system introduces frequency deviation through an acousto-optic modulator (AOM) to ensure the stability of a beat frequency signal. Further, the system couples the optical signals after frequency beating through an optical beam splitter, and detects the power of the coupled optical signals. The detected power value is transmitted to the FPGA control module to serve as an input parameter of PI control, a proportionality coefficient and an integral coefficient are adjusted in real time, a feedback control signal is generated and used for dynamically adjusting a front phase modulator of a receiving end Bob, and therefore the phase noise of a light source end is effectively reduced.

The invention discloses a frequency source synthesis system and method based on a frequency agility radar, and belongs to the technical field of microwave radio frequency, and the method specifically comprises the steps: generating a target clock signal, carrying out the frequency processing of the target clock signal to generate a frequency multiplication signal, and dividing the frequency multiplication signal into two clock signals through a power divider; performing frequency multiplication processing on one path of clock signal, taking the processed signal as a clock reference signal of a direct digital synthesizer, generating an analog signal according to the clock reference signal, and calibrating the analog signal as an output signal; performing frequency multiplication processing on the other path of clock signal, and taking the processed clock signal as a local oscillation signal of the frequency mixer; performing frequency conversion processing to obtain a frequency mixing signal, performing quadruplicated frequency processing on the frequency mixing signal, and calibrating the processed frequency mixing signal as a final output signal; according to the invention, the frequency source has the characteristics of low phase noise, rapid agility, fine resolution and miniaturization at the same time.

The invention relates to the technical field of measuring devices, in particular to an extreme learning machine assisted photoelectric oscillator magnetic field and temperature measuring device and method, and can solve the problems of poor stability and slow response speed of a magnetic field and temperature double-parameter measuring system in the existing measuring technology to a certain extent. According to the device, the OEO is used as a resonant cavity, the magnetostrictive material is pasted on the optical fiber, material stretching caused by an external magnetic field can be conducted to the optical fiber, FSR of the MZI is influenced, then the center frequency of the microwave photonic filter is influenced, magnetic field and temperature measurement is effectively converted into monitoring of oscillation signal frequency of the OEO, the measurement precision is improved, and the measurement accuracy is improved. By monitoring the center frequency and other mode frequencies of the OEO oscillation signal at the same time and demodulating through ELM, double-parameter measurement can be achieved under the simple and compact hardware condition, so that the problem of temperature cross sensitivity in magnetic field sensing is solved, and the measurement system has high system stability.

The invention discloses a high-speed direct digital frequency synthesizer based on an optimized CORDIC algorithm. The high-speed direct digital frequency synthesizer comprises a phase accumulator, a CORDIC converter and a digital-to-analog converter (DAC). Wherein the phase accumulator is responsible for accumulating input phases and properly intercepting the input phases. The CORDIC converter is based on an optimized CORDIC algorithm. The CORDIC converter is composed of a small-angle extraction module, a lookup table module, a rotation calculation module and a domain folding reduction module. The small angle extraction module converts a phase angle into a small angle within pi / 12, and the lookup table module only stores 11 groups of sine and cosine values divided for pi / 12. And the data after meter reading is firstly subjected to scaling-free processing, then is subjected to parallel three-group rotation calculation processing of a remainder four algorithm, finally, a signal is restored in the domain folding and restoring module through a sum angle formula, and finally, a digital signal is converted into an analog signal by a DAC (Digital-to-Analog Converter). By optimizing the CORDIC algorithm, the precision and speed of the frequency synthesizer are remarkably improved, and the storage requirement is greatly reduced, so that the production cost in large-scale chip manufacturing is greatly reduced.

The invention discloses a narrow-linewidth double-frequency laser generation method, and belongs to the technical field of microwave photons. Two paths of optical signals generated by two semiconductor lasers with different wavelengths are injected into the same optical microcavity, the two paths of optical signals enter a self-injection locking state in different modes of the optical microcavity, and the optical microcavity can output narrow-linewidth double-frequency laser. The invention further discloses a narrow-linewidth double-frequency laser generating device and a photo-production microwave method and device. Two double-frequency lasers with different frequencies are locked on one optical microcavity through an original double-self-injection locking technology, the problem of phase noise of a double-frequency light source is effectively solved while the linewidth of the input laser is narrowed, common-mode noise caused by mode difference of the two lasers in a locking state is eliminated, and the dual-frequency light source has the advantages of being simple in structure and convenient to operate. And the traditional servo locking technology is not needed, so that the complexity of the system is simplified.

The invention discloses a magnetic tuning F-type voltage-controlled oscillator based on multi-coil coupling, and the oscillator comprises an F-type oscillation loop which is used for generating an oscillation signal with a required frequency, and carrying out the harmonic adjustment of a frequency spectrum of the oscillation signal; the magnetic tuning transformer is used for adjusting the voltage-current relationship of the oscillation signal in the F-type oscillation loop, changing the equivalent inductance value in the F-type oscillation loop and further adjusting the oscillation frequency; the common-mode resonant capacitor is used for determining common-mode capacitance in the F-type oscillation loop and further reducing the phase noise at the second harmonic through common-mode resonance; the F-class voltage-controlled oscillator is adopted to enhance harmonic waves to achieve frequency tripling to generate millimeter wave oscillation signals, a magnetic tuning mode is adopted to replace a varactor with a low quality factor to control and change resonant frequency, and compared with a traditional LC voltage-controlled oscillator, the voltage-controlled oscillator can obtain lower phase noise and a higher quality factor, and the performance of the voltage-controlled oscillator is improved. And an additional frequency multiplier is omitted for the generation of the millimeter wave oscillation signal.

The invention discloses an ultra-wideband reconfigurable injection-locking multi-mode single-ended input / output frequency divider circuit, which comprises an input unit, a frequency dividing circuit connected with the input unit and an output unit connected with the frequency dividing circuit, and is characterized in that the frequency dividing circuit comprises an injection-locking two-half frequency dividing circuit and an injection-locking three-half frequency dividing circuit; the input unit uses a Balun structure circuit to enable the injection locking frequency-halving circuit and the injection locking frequency-tripling circuit to be the same single-end input, and the output unit uses a Multi-tank resonance network structure to realize single-end output of two frequency-tripling and frequency-tripling modes. In the design of the broadband millimeter wave phase-locked loop chip, better efficacy and ultra-wideband performance can be realized, the cost is lower, and the integration is easy.

The present invention discloses a charge pump phase-locked loop circuit for improving phase noise, including a frequency detector, a charge pump, a voltage-controlled oscillator, a frequency divider and a loop filter; a frequency detector branch composed of a frequency detector is provided, and the frequency detector branch is connected in parallel between the signal input end of the frequency detector and the signal output end of the charge pump; the frequency detector branch converts the frequency difference of the two input signals to obtain a current pulse signal and connects it to the loop filter, so that a zero point is added to the loop transfer function of the charge pump phase-locked loop; thereby changing the phase noise transfer function of each component of the circuit, making the output phase noise smaller and the output signal jitter smaller. Compared with the traditional charge pump phase-locked loop under the same parameters, the output phase noise of the phase-locked loop of the present invention is smaller, and the output signal jitter of 50KHz-10MHz is reduced from 3.98pS of the traditional charge pump phase-locked loop to 2.42pS; while ensuring sufficient phase margin, the loop bandwidth is increased, thereby further suppressing phase noise and reducing locking time.

A crystal oscillator and a method for reducing phase noise are provided. The crystal oscillator may include a crystal oscillator core circuit, a first bias circuit, and a phase noise reduction circuit. The first bias circuit is coupled to the output of the crystal oscillator core circuit, and the phase noise reduction circuit is also coupled to the output of the crystal oscillator core circuit. In operation, the crystal oscillator core circuit is configured to generate a sine wave. The first bias circuit is configured to provide a first voltage level as a bias voltage for the sine wave. The phase noise reduction circuit is configured to reset the bias voltage of the sine wave in response to the voltage level of the sine wave exceeding a specific voltage range. Using this method, the phase noise of the crystal oscillator can be reduced.

A fractional-N phase-locked loop (PLL) and its charge pump control method are provided. The fractional-N PLL includes a first current source, a first phase frequency detector (PFD), a second current source, a second PFD, and a frequency divider clock controller. The first current source provides a first current. The first PFD generates a first detection signal based on a first frequency divider clock to control the first current source, wherein the first frequency divider clock is generated based on an oscillation clock with an oscillation period. The second current source provides a second current. The second PFD generates a second detection signal based on a second frequency divider clock to control the second current source. The frequency divider controller controls the second frequency divider clock based on a variable delay relative to the first frequency divider clock, wherein the variable delay is an integer multiple of the oscillation period. Using this method, phase noise can be reduced.

The present disclosure provides a communication radar integrated optical fiber remote system and a phase locking method. A remote antenna unit is configured to receive a reflected microwave signal, and modulate the amplitude of the microwave signal to obtain an initial optical carrier signal. A dispersion compensation unit is connected with the remote antenna unit and configured to perform dispersion compensation on the initial optical carrier signal to obtain an optical carrier signal. A central unit is connected with the dispersion compensation unit and configured to perform phase locking using the received optical carrier signal to obtain an output optical signal. The frequency of the output optical signal is the same as that of the optical carrier signal, and the phase of the output optical signal is the same as that of the optical carrier signal. A signal output unit is connected with the central unit and configured to output the output optical signal. The present disclosure realizes the consistency of the frequency and the phase synchronization of the output optical signal and the optical carrier signal, realizes low phase noise carrier recovery, and improves the communication and radar performance.

This invention discloses a reconfigurable multi-mode ring oscillator, relating to the field of radio frequency integrated circuit design technology. The reconfigurable multi-mode ring oscillator includes multiple delay units and a switching network. The switching network is used to dynamically reconfigure the connection topology of the multiple delay units to switch between three modes. In the first mode, the switching network connects all delay units end-to-end to form a 6-stage ring oscillator. In the second mode, the switching network divides the multiple delay units into two parallel 3-stage sub-loops, and the corresponding core nodes of the two 3-stage sub-loops are coupled to each other through the switching network. In the third mode, the switching network divides the multiple delay units into three parallel 2-stage sub-loops, and the corresponding core nodes of the three 2-stage sub-loops are coupled to each other through the switching network. This provides a novel ring oscillator structure that can increase the tuning range and effectively suppress noise.

The invention discloses an artificial surface plasmon-based dual-mode oscillator, which comprises a resonance unit, a switching circuit and a differential circuit, and is characterized in that the resonance unit comprises a first metal ring and a second metal ring which are concentric, the inner ring of the first metal ring is connected with a plurality of first metal grid bars facing the second metal ring, and the inner ring of the second metal ring is connected with a plurality of second metal grid bars facing the second metal ring; a plurality of first metal grid bars facing the first metal ring are connected to the outer ring of the first metal ring, a plurality of second metal grid bars facing the first metal ring are connected to the outer ring of the second metal ring, the first metal grid bars and the second metal grid bars are arranged at intervals, a first notch is formed in the first metal ring, a second notch is formed in the position, corresponding to the first notch, of the second metal ring, and a third notch is formed in the position, 180 degrees away from the second notch, of the second metal ring. The two ends of the differential circuit are connected with the two ends of the first gap respectively and used for outputting differential excitation signals, and the two ends of the switching circuit are connected with the two ends of the third gap respectively and used for achieving the switching function, so that the modes of the dual-mode oscillator are switched. The invention has the advantages of wide frequency modulation range and low phase noise, and can be realized on a chip.

The invention provides a pulsed eddy current detection device and detection method based on roller pair adjustment, and relates to the technical field of nondestructive detection. The device comprises a supporting frame, a roller pair, a telescopic driving mechanism, a detection probe, a sliding adjusting mechanism, a distance measuring unit and a control unit. The control unit maintains the constant distance between the detection probe and the surface of the detected rod body based on a feedback signal of the distance measuring unit; based on the distance and the roller state signal, a telescopic driving mechanism is controlled to adjust the posture of the roller pair, so that the axis of the roller pair is aligned with the axis of the measured rod body; and when a preset spacing stability condition and an alignment condition are met, controlling the detection probe to transmit a pulsed eddy current excitation signal to the detected rod body, and receiving and outputting an eddy current response signal for defect identification. The double-shaft lift-off effect is actively inhibited through dynamic closed-loop control, the stability and accuracy of a detection signal are guaranteed, and then the recognition rate and detection reliability of the rod body surface and near-surface defects are remarkably improved.

The invention provides a method for automatically generating a pixelated resonant cavity of an oscillator based on knowledge-driven reverse design. The method comprises the following steps: determining a topological region range of VCO resonant cavity design; determining a reverse design target; a priori knowledge driving pixel matrix drawing strategy is established, pixelated inductor topological structure drawing is completed in the topological region based on the drawing strategy, and a primary pixelated inductor topological structure quality factor and a secondary pixelated inductor topological structure quality factor are calculated; according to a reverse design target, searching a Q value of a primary pixelated inductance topological structure from a binary n * n matrix assembly at a given target frequency, and meanwhile, achieving a maximized optimal solution to obtain an optimal pixel topological structure; and constructing the voltage-controlled oscillator in combination with the optimal pixel topological structure. According to the method, batch automatic simulation and optimization of the optimal resonant cavity structure can be realized, and compared with manual design, the time cost is saved, and meanwhile, the performance is further improved.

The present disclosure provides an integrated optoelectronic oscillator, comprising: a laser for generating a first optical carrier, the laser being a broadband tunable laser; the first light splitting waveguide is used for dividing the first optical carrier into a first branch optical carrier and a second branch optical carrier, the first branch optical carrier is propagated along a first branch, and the second branch optical carrier is propagated along a second branch; the electro-optical modulator is used for modulating the first electric signal to a first branch optical carrier to obtain a first modulated optical signal; the high-Q resonator is used for delaying and filtering the first modulated optical signal to obtain a second modulated optical signal; the light combination waveguide is used for carrying out beam combination on the second branch light carrier and the second modulation light signal to obtain a third modulation light signal; and the photoelectric detector is used for converting the third modulation optical signal into a second electric signal. According to the integrated optoelectronic oscillator, the laser with the tunable broadband and the high-Q resonator are adopted, the output frequency of the integrated optoelectronic oscillator can be changed, and the integrated optoelectronic oscillator with the tunable broadband is achieved.

This invention provides a crystal oscillator and a method for suppressing phase noise of the same. The crystal oscillator may include a crystal oscillator core circuit, a bias circuit coupled to the output of the crystal oscillator core circuit, a pulse wave buffer coupled to the output of the crystal oscillator core circuit, and a phase noise suppression circuit coupled to the output of the crystal oscillator core circuit. The crystal oscillator core circuit can generate a sine wave. The bias circuit can provide a bias voltage for the sine wave. The pulse wave buffer can generate a pulse wave according to the sine wave. The phase noise suppression circuit can generate a reset signal containing at least one reset pulse for resetting the bias voltage. Furthermore, a reset signal is generated without calibrating at least one reset pulse to the zero-crossing point of the sine wave.

The present invention discloses a high power efficiency ring oscillator which is insensitive to power supply disturbance, comprising an odd number of unit circuits, each unit gain circuit comprising a power supply sensitivity adjustment unit, a gain unit, an N-type switch current source and a varactor. The ring oscillator of the present invention basically does not increase the chip area and does not deteriorate the phase noise and power consumption of the oscillator. Therefore, the oscillator of the present structure fully utilizes the advantages of the ring oscillator having a small area, being insensitive to electromagnetic coupling, and being able to realize multi-phase clock signal output, greatly expanding the application of the ring oscillator, making it possible to use the ring oscillator in some applications that require both the ability to suppress power supply disturbances and relatively good phase noise.

This application provides a timing control device, system, and method for frequency-scanning radar based on frequency synthesizer and digital logic modules. The frequency synthesizer module serves as the synchronization source and timing reference source for the operating modes of the frequency-scanning radar system. In terms of system hardware architecture, it achieves coherent synchronization between the RF sub-module and the digital logic module. At the RF end, the SYNC signal is used to broaden the pulses of each sub-module, thereby forming the gate signals for each module's corresponding operating mode, which are distributed only by the digital logic module. At the digital end, edge and pulse width detection of the SYNC and MODE signals triggers the sampling and digital signal processing timing. The entire system uses the signal generated by the frequency synthesizer module as the reference, achieving high precision and low phase noise while reducing the external RF cables of the digital logic module. It also achieves strong coupling between the RF and digital ends, which is beneficial for FPGA on-chip resource optimization and timing convergence, reducing design verification costs and subsequent expansion costs.

The application provides a radio frequency source circuit and a laser frequency shift lock cavity signal generation method, which can be applied to the field of cold atom optical lattice clock technology. The radio frequency source circuit comprises a control sub-circuit, a phase-locked loop sub-circuit and an output power control sub-circuit. The control sub-circuit is used for receiving a digital control instruction from an upper computer and taking a synchronous clock as a working clock, performing amplitude-phase conversion and phase waveform conversion in parallel based on preset modulation data carried by the digital control instruction, and outputting a phase control word and a phase demodulation signal. The phase-locked loop sub-circuit is used for frequency multiplication of a reference clock and outputting a clock signal suitable for the working frequency of a frequency synthesizer as the working reference clock of the frequency synthesizer. The frequency synthesizer is used for taking the working reference clock as a frequency reference, realizing phase synchronization by combining the synchronous clock, and adjusting the phase of an output signal based on the phase control word. The output power control sub-circuit is used for adjusting the power of the output signal of the frequency synthesizer based on preset power modulation data to output a laser frequency shift lock cavity signal.

The application discloses a kind of based on in-phase injection coupling quadrature enhanced ring oscillator, belong to radio frequency integrated circuit technical field, comprising: ring oscillator circuit and quadrature coupler circuit;Ring oscillator circuit is used to generate oscillation signal, including cascaded two differential ring oscillator basic units, and each stage differential ring oscillator basic unit includes input pair transistor and negative resistance pair transistor;Quadrature coupler circuit includes coupling transistor: Q1, Q2 and Q3, four differential output nodes of first stage differential ring oscillator basic unit and second stage differential ring oscillator basic unit are connected respectively, and in-phase injection coupling structure is formed.Through introducing in-phase injection coupling structure in quadrature enhanced ring oscillator, high-precision phase locking and low phase noise are realized Collaborative optimization, on the premise of not consuming static power consumption, the phase difference of multiple-phase output signal is stably locked in by pure switch operation.

The invention provides a reference source and a satellite communication system.The reference source comprises an atomic clock, a first phase-locked loop, a low-frequency crystal oscillator, a frequency doubling filter circuit, a second phase-locked loop, a high-frequency crystal oscillator and an output device.A miniaturized design scheme is adopted, an ultra-thin rubidium clock, a constant-temperature crystal oscillator and an ultra-low phase noise crystal oscillator are arranged in the reference source; the system has the characteristics of small size and low cost, meets the application requirements of a miniaturized or highly integrated scene, and has a wide prospect; the multi-stage frequency synthesis technology is adopted, so that the output reference signal has the characteristics of high speed, stability and low phase noise, the requirements of the fields of time-frequency measurement, radar detection and the like on the reference source are met, and the application range is wide.

The application discloses a kind of phase correction method and system for structured light stripe profile projection, when boundary is identified, including the process of twice boundary identification, edge extraction is carried out by gray scale chart in initial boundary identification, in the second boundary identification, edge information extraction is carried out by phase calculation, boundary is identified by gray scale chart and phase diagram two directions, improve the accuracy of boundary identification, further the result of twice boundary identification is fused, so that the phase of stable area is not disturbed by jump pixel, ensure the accuracy of boundary division, based on the region after division, filtering processing is carried out to stable area, reduce the loss of feature information, provide reference information for the correction of unstable area, reduce error transmission, when the unstable area is compensated for error with stable area as reference, phase noise can be reduced, so as to reduce point cloud noise and improve precision.

The application discloses a soliton optical frequency comb and an optical microwave signal generation device, which comprises an optical source unit and an input light control unit, is suitable for obtaining amplified first pump laser, amplified second pump laser and amplified third pump laser; a micro resonant cavity unit comprising a micro resonant cavity, is suitable for generating a soliton optical frequency comb through a nonlinear four-wave mixing parametric oscillation process in the micro resonant cavity by using the amplified first pump laser; is suitable for compensating optical power changes caused by frequency mismatch of the amplified first pump laser by using the amplified second pump laser in the micro resonant cavity; and is suitable for suppressing thermal mechanical vibration noise of the micro resonant cavity based on optical force refrigeration effect by using the amplified third pump laser, so as to suppress phase noise of the soliton optical frequency comb; and a soliton optical frequency comb monitoring unit comprising a microwave signal generation module, the microwave signal generation module is suitable for generating an optical microwave signal by using the soliton optical frequency comb.

The present application relates to a kind of self-injection terahertz light frequency comb system, wherein, terahertz quantum cascade laser is as light frequency comb source, beat frequency signal generated by self beat frequency is transmitted into first T-type biasing device;First T-type biasing device is used to transmit beat frequency signal to wave divider;Wave divider is used to divide beat frequency signal into two ways, one way is transmitted to circulator and participates in self injection, another way is connected to spectrum analyzer and carries out real-time detection;Circulator is used to keep the one-way transmission of beat frequency signal participating in self injection in loop;Phase shifter is used to phase match beat frequency signal participating in self injection;Second T-type biasing device is used to inject phase-matched beat frequency signal into terahertz quantum cascade laser;Spectrum analyzer is used to detect the self-injection beat frequency signal obtained in real time.The present application can improve the stability of system, meet the requirement as high-frequency optoelectronic oscillator.

The utility model discloses a low noise continuous wave modulation laser drive source for high speed laser range finder, the utility model discloses a clock chip of CDCEL925 series is used to generate clock signal, and generates fundamental wave main vibration signal with this, wherein, compared with remaining frequency synthesis technique, it can produce the clock signal of lower phase noise, so, can generate the fundamental wave main vibration signal of low phase noise, simultaneously, through low noise direct current voltage module, the bias current of laser is generated, and it is combined with the fundamental wave main vibration signal of low phase noise through ac coupling, then can constitute the laser drive source of low phase noise, based on this, then can effectively reduce the random error of phase difference measurement, in addition, the utility model discloses still through optical power feedback module to carry out the power feedback of laser, and through integral regulator to feedback and adjust the bias current of laser loop, so, then can realize the transient stability of optical power in the modulation process, to further improve the ranging precision.

This invention discloses a voltage-controlled delay unit circuit, comprising: PMOS1 and PMOS3 with their sources connected to a power supply and their gates connected to a control voltage; PMOS1 with its drain connected to the source of PMOS2 and PMOS3 with its drain connected to the source of PMOS4; PMOS2 with its drain connected to the drain of NMOS1, the gate of PMOS4, and the gate of NMOS3; PMOS2 and NMOS1 with their gates connected to the input terminal IN and PMOS4 and NMOS3 with their drains connected to the output terminal OUT; NMOS1 with its source connected to the drain of NMOS2, NMOS2 with its gate connected to a bias voltage and its source grounded; NMOS3 with its source connected to the drain of NMOS4, NMOS4 with its gate connected to a bias voltage and its source grounded; PMOS5 and PMOS6 with their sources connected to a power supply and their gates connected to a control voltage, and their drains connected to the drains of NMOS1 and NMOS3 respectively; and NMOS5 and NMOS6 with their drains connected to the drains of PMOS1 and PMOS3 respectively, and their gates connected to a bias voltage and their sources grounded. This invention significantly shortens the level inversion time of the inverter, greatly reduces the circuit's sensitivity to power supply noise, substrate noise, and thermal noise, thereby directly reducing the phase noise and clock jitter of the delay phase-locked loop (DLL) output clock.

The utility model provides an FMCW multipath laser radar transmit-receive device comprising a seed light source, a phase-locked loop, a photon integrated chip, an erbium-doped fiber amplifier, a 1 * 4 optical switch, a circulator, a PBS beam splitter and a reflector. The seed light source is used for emitting signal light, and the signal light enters the erbium-doped optical fiber amplifier after passing through the phase-locked loop and the photonic integrated chip and then enters the 1 * 4 optical switch; the 1 * 4 optical switch is coupled with four circulators, a PBS (Phosphate Buffer Solution) and a reflecting mirror so as to correspond to scanning of four spaces, and detected signal light of an object enters the photon integrated chip and then is transmitted into the phase-locked loop for coherence with local oscillation light for signal processing; and the 1 * 4 optical switch is used for switching a scanning space.

The invention relates to the technical field of optical fiber communication, and discloses a coherent passive optical network carrier recovery method based on residual optical carriers. The coherent passive optical network carrier recovery system based on the residual optical carrier comprises: (1) a signal transmitting end: an external cavity modulation laser ECL 1 as a light source to output continuous light waves, the line width is less than 1MHz, and the working wavelength is a C wave band or other wave bands; the line width of the first distributed feedback laser DFB is several MHz, and the wavelength of the first distributed feedback laser DFB is a C wave band or other wave bands. According to the residual optical carrier-based coherent passive optical network carrier recovery method provided by the invention, a residual optical carrier (ROC) technology and digital subcarrier multiplexing (DScM) are introduced into a 100 Gbits / s / lambda DP-QPSKPON system, and a DFB laser is used for replacing an ECL to improve the cost and the architecture efficiency. According to the method, the total cost of the coherent PON system is remarkably reduced, and meanwhile, the phase noise related to the DFB with the MHz-level line width is effectively reduced.

The present invention discloses a low phase noise LC type voltage-controlled oscillator and electronic equipment. The LC type voltage-controlled oscillator comprises a resonance unit, a negative resistance unit and a feedback unit. The resonance unit and the negative resistance unit are respectively connected in parallel with two differential output terminals; the first input terminal of the feedback unit is connected to the resonance unit, the second input terminal is connected to the reference voltage terminal, and the output terminal is connected to the negative resistance unit. The LC type voltage-controlled oscillator adopts a technical solution of cross-coupling the negative resistance unit to bias the gate voltage of the tube separately, so that all MOS tubes can work in a suitable working area, ensure the normal operation of the LC type voltage-controlled oscillator, and reduce the phase noise of the voltage-controlled oscillator circuit, which is particularly suitable for application scenarios with low power supply voltage.